Our sustained investigation of the clinical pharmacology of antineoplastic agents continues to aid in the understanding of clinical problems through fundamental approaches. Adriamycin antitumor efficacy is reduced by pretreatment of mice with the microsomal inducer phenobarbital. The phenobarbital pretreatment alters the disposition and metabolism of adriamycin. A radioimmunoassay for adriamycin and daunorubicin showed that the pharmacokinetics of these agents can be determined. However, the values differ from those obtained by other methods. BIBLIOGRAPHIC REFERENCES: Bachur, N.R., Riggs, C.E., Green, M.R., Langone, J.J., VanVunakis, H., and Levin, L.: Human plasma adriamycin and daunorubicin by fluorescence and radioimmunoassay. Clin. Pharmacol. Therap. 21: 70-77, 1977. Benjamin, R.S., Riggs, C.E., and Bachur, N.R.: Plasm pharmacokinetics of adriamycin and its metabolites in humans with normal hepatic and renal function. Cancer Res. 37: 1416-1420, 1977.